USE A STABLE EMAIL ADDRESS. Send messages from an address that will remain constant for the duration of the course. Any change in email address will result in confusion and delays that may affect your mail for weeks. One way to make sure that you will fall out of the communication loop is to send messages from more than one email address. The instructor and your classmates won't respond, or, if they do, their messages will probably go to a mailbox that you don't routinely check. In either case, the result is a communication breakdown.